GitLab

- gh always exists, no need to check
- allow having non-bad gradient in first iteration

[skip ci]

Closes Dynare/dynare#1756

transformation to function handle made subsequent ischar-checks non-functioning

Related to #1757

local_state_space_iteration_k does not support it, use local_state_space_iteration_2 at order=2 instead and error out with order=3

Ref. dseries#45

[skip CI]

- forbid lead/lags on exogenous deterministic (Closes: #1765)
- fix crash when @#ifdef/@#ifndef is passed something else than a variable name
  (Closes: #1771)

Incidently, remove the possibility of passing model derivatives as arguments to
the k_order_perturbation. That possibility was only used by the risky steady
state code.

Closes: #1338

Under MATLAB R2014a, the strjoin() function wants a 1×n cell array, and rejects
a n×1 cell array. Octave and MATLAB R2020b are more permissive.

The histogram() function does not exist there.

Double quotes strings are not supported under older MATLAB versions.

MATLAB R2014a does not like some of the variable names that are passed to
table(). Disable that call, as under Octave.

– Whenever possible, pass the “tex” option to Dynare commands instead of
  fiddling with options_.TeX;
— For the remaining explicit options_.TeX and also for options_.debug,
  use a boolean value instead of an integer.

The mean(…, 'omitnan') syntax does not exist before R2015a. Use nanmean
instead (either provided by the statistics toolbox, or by our fallback under
matlab/missing/stats/).

Under MATLAB R2014a, the strjoin() function wants a 1×n cell array, and rejects
a n×1 cell array. Octave and MATLAB R2020b are more permissive.

The TeX option crashes MATLAB R2014a run with "-nodisplay" option
(as is done from the testsuite). We disable the TeX option in that case.

Since we can’t directly test whether "-nodisplay" has been passed, we test for
the "TOP_TEST_DIR" environment variable, which is set by the testsuite.

Note that it was not tested whether the crash happens with more recent MATLAB
versions, so when OLD_MATLAB_VERSION is increased, one should make a test
before removing this workaround.

Don't do bgp/solow-1 in Octave

See merge request !1780

Do not compute cholesky decomposition of H if the matrix has zeros on
the diagonal.

Also adds test cases